As the world becomes more focused on sustainability, there is increasing pressure on steel-bearing companies to improve their energy efficiency and reduce their carbon footprint. The heat treatment process accounts for about 25% of SKF's energy consumption, and it aims to achieve decarbonized operations by 2030 and the supply chain by 2050. Therefore, improving the energy efficiency of the heat treatment process can have significant economic and environmental benefits for the company. This thesis project aimed to conduct an energy mapping of different heat treatment processes at SKF to develop a methodology and standard key performance indicator for establishing energy performance and ensuring comparability between installations and processes. Three heat treatment processes were studied: through hardening, location A; case carburizing, location B; and surface induction hardening, location C. A detailed methodology and guidelines for carrying out energy mapping were developed. A standard key performance indicator known as Specific Energy consumption in kWh/kg at a particular utilization in % was set for comparisons among different heat treatment processes. Regression analysis was used to normalize the results. On the same utilization level, case carburizing, location B consumes more energy than through hardening, location A. Surface induction hardening, location C consumes 90% less than others and is less dependent on utilization. The carbon intensity in g CO2-eq/kg for greenhouse gas scopes 1, 2 and 3 were also studied. Case carburizing, location B had the highest climate impact due to the coal-based electricity mix of the country. Hence, the future availability of renewable electricity is critical when switching from gas to electricity across factories in SKF.

This diploma thesis is focused on the surface hardening of cast irons with spheroidal graphite. The work describes a theoretical analysis of the structure and properties of cast irons and individual methods suitable for surface hardening. The practical part describes the production of cast iron castings with spheroidal graphite, on which the surface hardening is performed, tensile test, hardening of produced castings by induction and laser surface hardening, preparation of samples for measuring microhardness and metallographic analysis of metal structures.